a(n)=least k such that s(k)=n, where s=A030717.

Terms

a(0) =1a(1) =3a(2) =6a(3) =11a(4) =16a(5) =20a(6) =25a(7) =36a(8) =44a(9) =52a(10) =45a(11) =74a(12) =192a(13) =73a(14) =53a(15) =103a(16) =86a(17) =63a(18) =121a(19) =75a(20) =636a(21) =951a(22) =88a(23) =1023a(24) =104a(25) =164a(26) =122a(27) =815a(28) =142a(29) =120